Marine Biology

, Volume 161, Issue 3, pp 711–724 | Cite as

The influence of symbiont type on photosynthetic carbon flux in a model cnidarian–dinoflagellate symbiosis

  • Dorota E. Starzak
  • Rosanne G. Quinnell
  • Matthew R. Nitschke
  • Simon K. Davy
Original Paper

Abstract

We measured the relationship between symbiont diversity, nutritional potential, and symbiotic success in the cnidarian–dinoflagellate symbiosis, by infecting aposymbiotic (i.e. symbiont-free) specimens of the model sea anemone Aiptasia sp. with a range of Symbiodinium types. Four cultured heterologous Symbiodinium types (i.e. originally isolated from other host species) were used, plus both cultured and freshly isolated homologous zooxanthellae (i.e. from Aiptasia sp.). Rates of photosynthesis, respiration, and symbiont growth were measured during symbiosis establishment and used to estimate the contribution of the zooxanthellae to the animal’s respiratory carbon demands (CZAR). Anemones containing Symbiodinium B1 (both homologous and heterologous) tended to attain higher CZAR values and hence benefit most from their symbiotic partners. This was despite Symbiodinium B1 not achieving the highest cell densities, though it did grow more quickly during the earliest stages of the infection process. Rather, the heterologous Symbiodinium types A1.4, E2, and F5.1 attained the highest densities, with populations of E2 and F5.1 also exhibiting the highest photosynthetic rates. This apparent success was countered, however, by very high rates of symbiosis respiration that ultimately resulted in lower CZAR values. This study highlights the impact of symbiont type on the functionality and autotrophic potential of the symbiosis. Most interestingly, it suggests that certain heterologous symbionts may behave opportunistically, proliferating rapidly but in a manner that is energetically costly to the host. Such negative host–symbiont interactions may contribute to the host–symbiont specificity seen in cnidarian–dinoflagellate symbioses and potentially limit the potential for partner switching as an adaptive mechanism.

Supplementary material

227_2013_2372_MOESM1_ESM.docx (34 kb)
Supplementary material 1 (DOCX 34 kb)

References

  1. Baghdasarian G, Muscatine L (2000) Preferential expulsion of dividing algal cells as a mechanism for regulating algal-cnidarian symbiosis. Biol Bull 199:278–286Google Scholar
  2. Baker AC (2001) Ecosystems: reef corals bleach to survive change. Nature 411:765–766Google Scholar
  3. Baker AC (2003) Flexibility and specificity in coral-algal symbiosis: diversity, ecology, and biogeography of Symbiodinium. Annu Rev Ecol Evo Syst 34:661–668Google Scholar
  4. Baker AC, Starger CJ, McClanahan TR, Glynn PW (2004) Corals’ adaptive response to climate change. Nature 430:741Google Scholar
  5. Belda-Baillie CA, Silvestre V, Villamor K, Monje V, Gomez ED, Baillie BK (1999) Evidence for changing symbiotic algae in juvenile tridacnids. J Exp Mar Biol Ecol 241:207–221Google Scholar
  6. Belda-Baillie CA, Baillie BK, Maruyama T (2002) Specificity of a model cnidarian—dinoflagellate symbiosis. Biol Bull 202:74–85Google Scholar
  7. Berkelmans R, van Oppen MJH (2006) The role of zooxanthellae in the thermal tolerance of corals a ‘nugget of hope’ for coral reefs in an era of climate change. Proc R Soc Lond B Biol Sci 273:2305–2312Google Scholar
  8. Bossert P, Dunn KW (1986) Regulation of intracellular algae by various strains of symbiotic Hydra viridissima. J Cell Sci 85:187–195Google Scholar
  9. Buddemeier RW, Fautin DG (1993) Coral bleaching as an adaptive mechanism. Bioscience 43:320–326Google Scholar
  10. Burriesci MS, Raab TK, Pringle JR (2012) Evidence that glucose is the major transferred metabolite in dinoflagellate–cnidarian symbiosis. J Exp Biol 215:3467–3477Google Scholar
  11. Cantin N, van Oppen MJH, Willis BL, Mieog JC, Negri AP (2009) Juvenile corals can acquire more carbon from high-performance algal symbionts. Coral Reefs 28:405–414Google Scholar
  12. Chisholm SW (1981) Temporal patterns of cell division in unicellular algae. In: Platt T (ed) Physiological bases of phytoplankton ecology. Bull Can J Fish Aquatic Sci 210:150–181Google Scholar
  13. Coffroth MA, Santos SR (2005) Genetic diversity of symbiotic dinoflagellates in the genus Symbiodinium. Protist 156:19–34Google Scholar
  14. Coffroth MA, Goulet TL, Santos SR (2001) Early ontogenic expression of specificity in a cnidarian-algal symbiosis. Mar Ecol Prog Ser 222:85–96Google Scholar
  15. Coffroth MA, Poland DM, Petrou EL, Brazeau DA, Holmberg JC (2010) Environmental symbiont acquisition may not be the solution to warming seas for reef-building corals. PLoS ONE 5(10):e13258. doi:10.1371/journal.pone.0013258 Google Scholar
  16. Cook CB, D’Elia CF (1987) Are natural populations of zooxanthellae ever nutrient-limited? Symbiosis 4:199–212Google Scholar
  17. D’Elia CF, Domotor SL, Webb KL (1983) Nutrient uptake kinetics of freshly isolated zooxanthellae. Mar Biol 75:157–167Google Scholar
  18. Davies PS (1984) The role of zooxanthellae in the nutritional energy requirements of Pocillopora eydouxi. Coral Reefs 2(4):181–186Google Scholar
  19. Davies PS (1991) Effect of daylight variations on the energy budgets of shallow-water corals. Mar Biol 108:137–144Google Scholar
  20. Davy SK, Cook CB (2001) The relationship between nutritional status and carbon flux in the zooxanthellate sea anemone Aiptasia pallida. Mar Biol 139:999–1005Google Scholar
  21. Davy SK, Lucas IAN, Turner JR (1996) Carbon budgets in temperate anthozoan-dinoflagellate symbiosis. Mar Biol 126:773–783Google Scholar
  22. Davy SK, Lucas IAN, Turner JR (1997) Uptake and persistence of homologous and heterologous zooxanthellae in the temperate sea anemone Cereus pedunculatus (Pennant). Biol Bull 192:208–216Google Scholar
  23. Davy SK, Allemand D, Weis VM (2012) Cell biology of cnidarian-dinoflagellate symbiosis. Microbiol Mol Biol R 76(2):1–33Google Scholar
  24. Day RJ (1994) Algal symbiosis in Bunodeopsis: sea anemones with auxiliary structures. Biol Bull 186:182–194Google Scholar
  25. Domotor SL, D’Elia CF (1984) Nutrient uptake kinetics and growth of zooxanthellae maintained in laboratory culture. Mar Biol 80:93–101Google Scholar
  26. Douglas AE, Smith DC (1984) The green hydra symbiosis. VIII. Mechanisms in symbiont regulation. Proc R Soc Lond B Biol Sci 221:291–319Google Scholar
  27. Dunn SR, Weis VM (2009) Apoptosis as a post-phagocytic winnowing mechanism in a coral-dinoflagellate mutualism. Environ Microbiol 11:268–276Google Scholar
  28. Dunn SR, Bythell JC, Le Tissier MDA, Burnett WJ, Thomason JC (2002) Programmed cell death and cell necrosis activity during hyperthermic stress-induced bleaching of the symbiotic sea anemone Aiptasia sp. J Exp Mar Biol Ecol 272:29–53Google Scholar
  29. Edmunds PJ, Davies PS (1986) An energy budget for Porites porites (Scleractinia). Mar Biol 92(3):339–347Google Scholar
  30. Edmunds PJ, Davies PS (1989) An energy budget for Porites porites (Scleractinia), growing in a stressed environment. Coral Reefs 8:37–43Google Scholar
  31. Fabina NS, Putnam HM, Franklin EC, Stat M, Gates RD (2012) Transmission mode predicts specificity and interaction patterns in coral-Symbiodinium networks. PLoS ONE 7(9):e44970. doi:10.1371/journal.pone.0044970 Google Scholar
  32. Falkowski PG, Dubinsky Z, Muscatine L, McCloskey L (1993) Population-control in symbiotic corals. Bioscience 43:606–611Google Scholar
  33. Farrant PA, Borowitzka MA, Hinde R, King RJ (1987a) Nutrition of the temperate Australian soft coral Capnella gaboensis. I. Photosynthesis and carbon fixation. Mar Biol 95:565–574Google Scholar
  34. Farrant PA, Borowitzka MA, Hinde R, King RJ (1987b) Nutrition of the temperate Australian soft coral Capnella gaboensis. II. The role of zooxanthellae and feeding. Mar Biol 95:575–581Google Scholar
  35. Fautin DG, Buddemeier RW (2004) Adaptive bleaching: a general phenomenon. Hydrobiologia 530(531):459–460Google Scholar
  36. Fitt WK (1985) Effect of different strains of the zooxanthella Symbiodinium microadriaticum on growth and survival of their coelenterate and molluscan hosts. Proc 5th Int Congr Coral Reefs 6:131–136Google Scholar
  37. Fitt WK, Trench RK (1981) Spawning, development, and acquisition of zooxanthellae by Tridacna squamosa (Mollusca: Bivalvia). Biol Bull 161:213–235Google Scholar
  38. Fitt WK, Trench RK (1983) Endocytosis of the symbiotic dinoflagellate Symbiodinium microadriaticum Freudenthal by endodermal cells of the scyphistomae of Cassiopeia xamachana and resistance of the algae to host digestion. J Cell Sci 64:195–212Google Scholar
  39. Fitt WK, McFarland FK, Warner ME, Chilcoat GC (2000) Seasonal patterns of tissue biomass and densities of symbiotic dinoflagellates in reef corals and relation to coral bleaching. Limnol Oceanogr 45:677–685Google Scholar
  40. Furla P, Allemand D, Shick JM, Ferrier-Pagès C, Richer S, Plantivaux A, Merle PL, Tambutté S (2005) The symbiotic anthozoan: a physiological chimera between alga and animal. Integr Comp Biol 45:595–604Google Scholar
  41. Gates RD, Baghdasarian G, Muscatine L (1992) Temperature stress causes host cell detachment in symbiotic cnidarians implications for coral bleaching. Biol Bull 182:324–332Google Scholar
  42. Goulet TL, Cook CB, Goulet D (2005) Effects of short-term exposure to elevated temperatures and light levels on photosynthesis of different host-symbiont combinations in the Aiptasia pallida/Symbiodinium symbiosis. Limnol Oceanogr 50:1490–1498Google Scholar
  43. Harland AD, Davies PS (1995) Symbiont photosynthesis increases both respiration and photosynthesis in the symbiotic sea anemone Anemonia viridis. Mar Biol 123(4):715–722Google Scholar
  44. Hoogenboom M, Beraud E, Ferrier-Pagès C (2010) Relationship between symbiont density and photosynthetic carbon acquisition in the temperate coral Cladocora caespitosa. Coral Reefs 29:21–29Google Scholar
  45. Jones RJ, Yellowlees D (1997) Regulation and control of intracellular algae (equals zooxanthellae) in hard corals. Proc R Soc Lond B Biol Sci 352:457–468Google Scholar
  46. Jones AM, Berkelmans R, van Oppen MJH, Mieog JC, Sinclair W (2008) A community change in the algal endosymbionts of a scleractinian coral following a natural bleaching event: field evidence of acclimatization. Proc R Soc Lond B Biol Sci 275:1359–1365Google Scholar
  47. Kellogg RB, Patton JS (1983) Lipid droplets, medium of energy exchange in the symbiotic anemone Condylactis gigantea—a model coral polyp. Mar Biol 75:137–149Google Scholar
  48. Kinzie RA (1974) Experimental infection of aposymbiotic gorgonian polyps with zooxanthellae. J Exp Mar Biol Ecol 15:335–345Google Scholar
  49. Kinzie RA, Chee GS (1979) The effect of different zooxanthellae on the growth of experimentally reinfected hosts. Biol Bull 156:315–327Google Scholar
  50. Lesser M (2013) Using energetic budgets to assess the effects of environmental stress on corals: are we measuring the right things? Coral Reefs 32(1):25–33Google Scholar
  51. Lesser MP, Farrell JH (2004) Exposure to solar radiation increases damage to both host tissues and algal symbionts of corals during thermal stress. Coral Reefs 23:367–377Google Scholar
  52. Lesser MP, Stat M, Gates RD (2013) The endosymbiotic dinoflagellates (Symbiodinium sp.) of corals are parasites and mutualists. Coral Reefs 32(3):603–611Google Scholar
  53. Lewis CL, Coffroth MA (2004) The acquisition of exogenous algal symbionts by an octocoral after bleaching. Science 304:1490–1492Google Scholar
  54. Little AF, van Oppen MJH, Willis BL (2004) Flexibility in algal endosymbioses shapes growth in reef corals. Science 304:1492–1494Google Scholar
  55. Logan DK, LaFlamme AC, Weis VM, Davy SK (2010) Flow cytometric characterization of the cell surface glycans of symbiotic dinoflagellates (Symbiodinium spp.). J Phycol 46:525–533Google Scholar
  56. Loram JE, Trapido-Rosenthal HG, Douglas AE (2007) Functional significance of genetically different symbiotic algae Symbiodinium in a coral reef symbiosis. Mol Ecol 16:4849–4857Google Scholar
  57. McAuley PJ (1981) Control of cell division of the intracellular Chlorella symbionts in green hydra. J Cell Sci 47:197–206Google Scholar
  58. McCloskey LR, Muscatine L, Wilkerson FP (1994) Daily photosynthesis, respiration, and carbon budgets in a tropical marine jellyfish (Mastigias sp.). Mar Biol 119:13–22Google Scholar
  59. Mieog JC, van Oppen MJH, Cantin NE, Stam WT, Olsen JL (2007) Real-time PCR reveals a high incidence of Symbiodinium clade D at low levels in four scleractinian corals across the Great Barrier Reef: implications for symbiont shuffling. Coral Reefs 26:449–457Google Scholar
  60. Molea T, Munro P (1994) Influence of symbiont strain on early growth of tridacnids. Asian Fish Sci 7:91–102Google Scholar
  61. Muller-Parker G, Davy SK (2001) Temperate and tropical algal-sea anemone symbioses. Invertebr Biol 120:104–123Google Scholar
  62. Muscatine L (1967) Glycerol extraction by symbiotic algae from corals and Tridacna and its control by the host. Science 156:516–519Google Scholar
  63. Muscatine L (1990) The role of symbiotic algae in carbon and energy flux in reef corals. In: Dubinsky Z (ed) Ecosystems of the world: Coral reefs. Elsevier, Amsterdam, pp 75–87Google Scholar
  64. Muscatine L, Pool RR (1979) Regulation of numbers of intracellular algae. Proc R Soc Lond B Biol Sci 204:131–139Google Scholar
  65. Muscatine L, Porter JW (1977) Reef corals: mutualistic symbioses adapted to nutrient poor environments. Bioscience 27(7):454–460Google Scholar
  66. Muscatine L, McCloskey LR, Marian RE (1981) Estimating the daily contribution of carbon from zooxanthellae to coral animal respiration. Limnol Oceanogr 26:601–611Google Scholar
  67. Muscatine L, Falkowski PG, Dubinsky Z (1983) Carbon budgets in symbiotic associations. In: Schenk HEA, Schwemmler W (eds) Endocytobiology II Intracellular space as oligogenetic ecosystem. Walter de Gruyter, Berlin and New York, pp 649–658Google Scholar
  68. Muscatine L, Falkowski PG, Porter JW, Dubinsky Z (1984) Fate of photosynthetic fixed carbon in light-adapted and shade-adapted colonies of the symbiotic coral Stylophora pistillata. Proc R Soc Lond B Biol Sci 222:181–202Google Scholar
  69. Obura DO (2005) Resilience and climate change: lessons from coral reefs and bleaching in the western Indian Ocean. CORDIO East AfricaGoogle Scholar
  70. Oliver TA, Palumbi SR (2009) Distributions of stress-resistant coral symbionts match environmental patterns at local but not regional scales. Mar Ecol Prog Ser 378:93–103Google Scholar
  71. Oliver TA, Palumbi SR (2011) Many corals host thermally resistant symbionts in high-temperature habitat. Coral Reefs 30:241–250Google Scholar
  72. Patton JS, Battey JF, Rigler MW, Porter JW, Black CC, Burris JF (1983) A comparison of the metabolism of bicarbonate 14C and acetate 1-14C and the variability of species lipid compositions in reef corals. Mar Biol 75:121–130Google Scholar
  73. Peng SE, Wang YB, Wang LH, Chen WNU, Lu CY, Fang LS, Chen CS (2010) Proteomic analysis of symbiosome membranes in Cnidaria–dinoflagellate endosymbiosis. Proteomics 10:1002–1016Google Scholar
  74. Peng SE, Chen WNU, Chen HK, Lu CY, Mayfiled AB, Fang L, Chen CS (2011) Lipid bodies in coral-dinoflagellate endosymbiosis: proteomic and ultrastructural studies. Proteomics 11:3540–3555Google Scholar
  75. Peterson CH, Lubchenco J (1997) On the value of marine ecosystems to society. In: Daily GC (ed) Nature’s services. Island Press, New York, Societal dependence on natural ecosystems, pp 177–194Google Scholar
  76. Rinkevich B (1989) The contribution of photosynthetic products to coral reproduction. Mar Biol 101(2):259–263Google Scholar
  77. Rodriguez-Lanetty M, Chang SJ, Song JI (2003) Specificity of two temperate dinoflagellate–anthozoan associations from the north-western Pacific Ocean. Mar Biol 143:1193–1199Google Scholar
  78. Rodriguez-Lanetty M, Wood-Charlson E, Hollingsworth L, Krupp DA, Weis VM (2006) Dynamics of infection and localization of dinoflagellate endosymbionts in larvae of the coral Fungia scutaria during the onset of symbiosis. Mar Biol 149:713–719Google Scholar
  79. Rodriquez-Lanetty M, Krupp DA, Weis VM (2004) Distinct ITS types of Symbiodinium in Clade C correlate with cnidarian/dinoflagellate specificity during onset of symbiosis. Mar Ecol Prog Ser 275:97–102Google Scholar
  80. Rowan R (2004) Thermal adaptation in reef coral symbionts. Nature 430:742Google Scholar
  81. Schoenberg DA, Trench RK (1980a) Genetic variation in Symbiodinium (= Gymnodinium) microadriaticum Freudenthal, and specificity in its symbiosis with marine invertebrates. II. Morphological variation in Symbiodinium microadriaticum. Proc R Soc Lond B Biol Sci 207:429–444Google Scholar
  82. Schoenberg DA, Trench RK (1980b) Genetic variation in Symbiodinium (= Gymnodinium) microdriaticum Freudenthal and specificity in its symbiosis with marine invertebrates (III) Specificity and infectivity of Symbiodinium microdriaticum. Proc R Soc Lond B Biol Sci 207:445–460Google Scholar
  83. Smith GJ, Muscatine L (1986) Carbon budgets and regulation of the population density of symbiotic algae. Endocyt Cell Res 3:213–238Google Scholar
  84. Stat M, Morris E, Gates RD (2008) Functional diversity in coral-dinoflagellate symbiosis. Proc Natl Acad Sci USA 105:9256–9261Google Scholar
  85. Stat M, Bird CE, Pochon X, Chasqui L, Chauka LJ, Concepcion GT, Logan D, Takabayashi M, Toonen RJ, Gates RD (2011) Variation in Symbiodinium ITS2 sequence assemblages among coral colonies. PLoS ONE 6(1):e15854. doi:10.1371/journal.pone.0015854 Google Scholar
  86. Steen RG, Muscatine L (1984) Daily budgets of photosynthetically fixed carbon in symbiotic zoanthids. Biol Bull 167:477–487Google Scholar
  87. Strathmann RR (1967) Estimating the organic carbon content of phytoplankton from cell volume or plasma volume. Limnol Oceanogr 12:411–418Google Scholar
  88. Streamer M, McNeil YR, Yellowlees D (1993) Photosynthetic carbon dioxide fixation in zooxanthellae. Mar Biol 115:195–198Google Scholar
  89. Takabayashi M, Adams L, Pochon X, Gates RD (2012) Genetic diversity of free-living Symbiodinium in surface water and sediment of Hawaii and Florida. Coral Reefs 31(1):157–167Google Scholar
  90. Thornhill DJ, Xiang Y, Pettay DT, Zhong M, Santos SR (2013) Population genetic data of a model symbiotic cnidarian system reveal remarkable symbiotic specificity and vectored introductions across ocean basins. Mol Ecol 22(17):4499–4515Google Scholar
  91. Tremblay P, Grover R, Maguer JF, Legendre L, Ferrier-Pagès C (2012) Autotrophic carbon budget in the coral tissue: a new 13C-based model of photosynthate translocation. J Exp Biol 215:1384–1393Google Scholar
  92. Trench RK (1971) The physiology and biochemistry of zooxanthellae symbiotic with marine coelenterates. II. Liberation of fixed 14C by zooxanthellae in vitro. Proc R Soc Lond B Biol Sci 177:237–250Google Scholar
  93. Trench RK (1974) Nutritional potentials in Zoanthus sociatus (Coelenterata, Anthozoa). Helgolander Wiss Meeresunters 26:174–216Google Scholar
  94. Trench RK (1987) Dinoflagellates in non-parasitic symbiosis. In: Taylor FJR (ed) Biology of dinoflagellates. Blackwell, Oxford, pp 530–570Google Scholar
  95. Trench RK (1997) Diversity of symbiotic dinoflagellates and the evolution of microalgal–invertebrate symbioses. Proc 8th Int Coral Reef Sym 2:1275–1286Google Scholar
  96. Verde EA, McCloskey LR (1996a) Carbon budget studies of symbiotic cnidarian anemones—evidence in support of some assumptions. J Exp Mar Biol Ecol 195:161–171Google Scholar
  97. Verde EA, McCloskey LR (1996b) Photosynthesis and respiration of two species of algal symbionts in the anemone Anthopleura elegantissima (Cnidaria; Anthozoa). J Exp Mar Biol Ecol 195:187–202Google Scholar
  98. Verde EA, McCloskey LR (2002) A comparative analysis of the photobiology of zooxanthellae and zoochlorellae symbiotic with the temperate clonal anemone Anthopleura elegantissima (Brandt). II. Effect of light intensity. Mar Biol 141:225–239Google Scholar
  99. Verde EA, McCloskey LR (2007) A comparative analysis of the photobiology of zooxanthellae and zoochlorellae symbiotic with the temperate clonal anemone Anthopleura elegantissima (Brandt). III. Seasonal effects of natural light and temperature on photosynthesis and respiration. Mar Biol 152:775–792Google Scholar
  100. Wakefield TS, Kempf SC (2001) Development of host and symbiont-specific monoclonal antibodies and confirmation of the origin of the symbiosome membrane in a cnidarian-dinoflagellate symbiosis. Biol Bull 200:127–143Google Scholar
  101. Weis VM (1993) Effect of dissolved inorganic carbon concentration on the photosynthesis of the symbiotic sea anemone Aiptasia pulchella Carlgren: role of carbonic anhydrase. J Exp Mar Biol Ecol 174(2):209–225Google Scholar
  102. Weis VM, Allemand D (2009) What determines coral health? Science 324:1153–1154Google Scholar
  103. Weis VM, Reynolds WS, deBoer MD, Krupp DA (2001) Host-symbiont specificity during onset of symbiosis between the dinoflagellates Symbiodinium spp. and planula larvae of the scleractinian coral Fungia scutaria. Coral Reefs 20:301–308Google Scholar
  104. Weis VM, Davy SK, Hoegh-Guldberg O, Rodriguez-Lanetty M, Pringle J (2008) Cell biology in model systems as the key to understanding corals. Trends Ecol Evol 23:369–376Google Scholar
  105. Whitehead LF, Douglas AE (2003) Metabolite comparisons and the identity of nutrients translocated from symbiotic algae to an animal host. J Exp Biol 206:3149–3157Google Scholar
  106. Xiang T, Hambleton EA, DeNofrio JC, Pringle JR, Grossman AR (2013) Isolation of clonal, axenic strains of the symbiotic dinoflagellate Symbiodinium and their growth and host specificity. J Phycol 49:447–458Google Scholar

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© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Dorota E. Starzak
    • 1
    • 4
  • Rosanne G. Quinnell
    • 2
  • Matthew R. Nitschke
    • 1
    • 3
  • Simon K. Davy
    • 1
  1. 1.School of Biological SciencesVictoria University of WellingtonWellingtonNew Zealand
  2. 2.School of Biological SciencesThe University of SydneySydneyAustralia
  3. 3.School of Biological SciencesThe University of QueenslandBrisbaneAustralia
  4. 4.School of Health SciencesUniversity of KwaZulu-NatalDurbanSouth Africa

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